Inverter Return Amps question

[Frostman]

My inverter doesn’t have a ‘Return Amps’ setting. Does anybody know if there is an equivalent Voltage setting that can achieve the same effect? All of my inverter settings are primarily voltage settings. Endeavor advised me to set my Return Amps setting but there is no such setting option. HELP!!!

[Ike]

Return Amps
During the absorption phase, the battery accepts progressively less current. Once the charge current remains under a certain level for a given period of time, the battery is considered to be fully charged. This maximum charge current is called the Return Amps, and the corresponding period the Return Amps Time. The battery charger takes this as a signal to switch over to the next step, the float phase. Just like many other parameters of the battery charger, Return Amps and Return Amps Time can be set by the installer with the help of software that is freely available on the Mastervolt website. In fact, the installer can use this software to customise the battery charger to your onboard system requirements.

That's from the Mastervolt FAQ page. https://www.mastervolt.com/frequentl...tery-chargers/ I am assuming you have a combo inverter/charger. If its a simple inverter only then none of this applies So what they are telling you is to set the Maximum Charge Rate. That would be the Maximum Voltage output setting for charging the batteries. What the maximum voltage setting is depends on the batteries you are charging. Some batteries are very voltage sensitive, such as AGMs, and Gel Batteries. Simple wet cell Lead Acid batteries aren't quite as sensitive but I wouldn't set it much higher than about 14.1 V. Check your battery specs.

[Frostman]

Thanks Peter. The 145 page manual for our inverter/charger unit (Trace Engineering SW2512) mentions the ranges for each setting, but nowhere therein does it explain why one would choose a higher or lower setting. I’m looking for a source that addresses their use in layman terminology for those of us that don’t have a degree in electrical engineering!

[Ike]

I tried reading that manual. Not very clear. Its online at http://www.xantrex.com/documents/Dis...2UserGuide.pdf
Most People think batteries are all the same. They aren't. Lead Acid wet cells are divided in three types, starting batteries, Deep cycle batteries, combo batteries (often sold as "marine" batteries). Each is constructed differently. Each has to be charged in a specific way. Most battery chargers these days have a simple selector panel for the type of battery. Not this one. And AGM and Gel Batteries are even more different

However the charge cycle is the same for al batteries.
Bulk
Absorption
Float
Equalization (not all chargers do this stage)

Bulk: used when the battery is deeply discharged and can accept recharge at the highest rate. Different batteries have different acceptance rates based on the design of the battery. What this means simply is that some batteries can be charged faster than other batteries. For instance AGM batteries can be charged faster than wet cells. Smart chargers have different settings for starting batteries, deep cycle batteries, AGM and Gel cells.

Absorption: voltage stays constant and the current slowly tapers off.

Float:* used after the battery has reached full charge to maintain the battery. This used to be called trickle charge but unlike trickle charge, does not maintain a constant voltage and current from the charger to the battery. The charger senses the battery state and applies current when it is needed to maintain the state of the battery.

Equalization: Some smart chargers have a level called equalization. The charger senses the charge level of each cell in the battery and brings each cell in the battery to the same charge level. Equalization is usually performed before the float stage.

The maximum voltage has to be set for each stage depending on the type of batteries. There is a section in the manual that specifies battery types. It's on page 99 under Technical Information (in the pdf) and set points are on page 104. It specifies maximum voltage for each stage.

Hope this helps: